Load break interrupter switch with delayed action auxiliary closing device



Apnl 13, 1965 R. H. ALBRIGHT ETAL 3,178,543

LOAD BREAK INTERRUPTER SWITCH WITH DELAYED ACTION AUXILIARY CLOSING DEVICE Filed Aug. 10, 1962 4 Sheets-Sheet 1 p l 13, 1965 R. H. ALBRIGHT ETAL 3,178,543

LOAD BREAK INTERRUPTER SWITCH WITH DELAYED ACTION AUXILIARY CLOSING DEVICE Filed Aug. 10, 1962 4 Sheets-Sheet 2 April 13, 1965 R. H. ALBRIGHT ETAL 3,178,

LOAD BREAK INTERRUPTER SWITCH WITH DELAYED ACTION AUXILIARY CLOSING DEVICE 4 Sheets-Sheet 3 Filed Aug. 10, 1962 INVENTORS 41 ave/w Apnl 13, 1965 R. H. ALBRIGHT ETAL 3,178,543

LOAD BREAK INTERRUPTER SWITCH WITH DELAYED ACTION AUXILIARY CLOSING DEVICE Filed Aug. 10, 1962 4 Sheets-Sheet 4 J I a 15:1.

INVENTORS' ay A 4152/66 7- BY 6208;: A 3yzae United States Patent LOAD BREAK INTERRUPTER SWITCH WITH DELAYED ACTION AUXILIARY (TLOSING DEVICE Roy H. Albright and George H. Taylor, Greensburg, I 'a.,

assignors to l-T-lE Circuit Breaker Company, Philadelphia, Pa, a corporation of Pennsylvania Filed Aug. 10, 1962, Ser. No. 216,161 5 Claims. (Cl. 200-146) This invention relates to circuit interrupters having an auxiliary blade and are chute for the confinement of an arc during interruption of load currents, and more parncularly to such a load break interrupter switch wherein the auxiliary blade is kept out of the arc chute during switch closing until engagement is made between the main blade and stationary contact.

Load break interrupter switches presently in use are designed to close into or open upon energized lines, thereby necessitating an arrangement for the extinguishment of an are which may be formed during the opening operation. These requirements led to the development of the load break interrupter switch which includes main and auxiliary interrupting blade means. The blades are operatively associated such that during opening the auxiliary blade in biased to rapidly interrupt the circuit after the main disconnecting blade has moved to establish a sufficient open gap clearance.

The main blade which is pivotally connected to one terminal of the circuit to be protected is positioned to cooperate with a stationary break contact which is electrically connected to the other terminal associated with the circuit being protected. The auxiliary switch blade is pivotally connected at one end to the main switch blade in such a manner that the opposite end of the auxiliary switch blade cooperates with a pair of auxiliary contacts electrically connected to the main stationary break con.- tact. Surrounding the auxiliary contacts which cooperate with the auxiliary switch blade is an arc chute appropriately designed to confine any are formed between the auxiliary switch blade and its associated contacts to the arc chute itself. The are chute is molded from a plastic material, especially selected for its arc extinguishing properties.

When the main switch blade is moved in a direction away from its associated break contact, the pivotally mounted auxiliary switch blade nevertheless remains in engagement with its associated auxiliary contacts. After a predetermined amount of rotation of the main switch blade, further angular separation of the auxiliary blade therefrom is limited, thereby causing the auxiliary switch blade to be disengaged from the associated auxiliary con tacts. Charged biasing means connected between the main and auxiliary contact blades cause rapid separation of the auxiliary blade from its associated contacts, thereby aiding in the extinguishment of the are formed between the auxiliary blade and its associated contacts.

To close the contacts of such load break interrupter switch it has been the practice to simultaneously move the main and auxiliary contacts, with a slight lag, between the blades such that engagement is made by the main blade prior to engagement by the auxiliary blade. The physical proximity of the blades is such that the prior art switches have permitted the auxiliary blade to enter the arc chute prior to engagement of the main blade. Thus, since the auxiliary blade is substantially parallel to the main switch blade as the switch is closed and although the main contacts are made before the auxiliary blade engages its contact, the auxiliary blade and contact will be sufiiciently close to permit arcing therebetween. Once arcing occurs deposits are formed within the arc chute chamber which appreciably lower the resistance, thereby facilitating are- 3,178,543 Patented Apr. 13, 1965 ing upon subsequent opening and closing of the switch. The are chutes of such load break interrupter switches have therefore been found to have a relatively short life due to deleterious effect of arcing within the arc chute during the closing operation.

Our invention provides a load break interrupter switch which prevents such arcing within the arc chute chamber upon closing, thereby permitting increased operating life over similar interrupter switches of the prior art, while still providing safe reliable operation throughout such extended operating life.

The load break interrupter switch of the instant invention includes a stop means operatively positioned along the path of the auxiliary blade to prevent entry of the auxiliary blade within the arc chute chamber until contact has been made by the main blade. The auxiliary blade on the load break interrupter switch is springbiased in both directions and is normally held parallel to the main switch blade. As the switch is closed, the end of the auxiliary blade hits a stop before it enters the arc chute. The stop is appropriately placed in conjunction with the blade configuration and biasing force, to hold the auxiliary blade without the arc chute until a predetermined angular relationship exists between the main and auxiliary blades corresponding to engagement of the main blade. As the main blade is moved toward engagement, increasing the angular separation about the pivotal engage nent of the main and auxiliary blades, torsional loading of the biasing spring is increased, so that when the auxiliary blade is finally released from the stop it is rapidly snapped to its fully closed position after the main contacts are in engagement.

In opening of the switch the auxiliary blade is held by its contacts until the main contacts have parted sufficiently. The torsion loading of the spring is increased in the opposite direction. After sufiicient open gap clearance has been established for the main contacts, further deflection of the auxiliary blade relative to the main blade is prevented and the auxiliary contact is broken. The auxiliary blade then snaps to its normal position parallel to the main blade.

Should the above-described stop means be rigidly secured in place, the auxiliary blade will disadvantageously be held by the stop during opening. To avoid this, the stop is preferably biased to move freely in one direction, thereby not impeding the movement of the auxiliary blade during switch opening. The torsional spring is preferably preloaded so that the auxiliary blade is held fairly securely in its normal position and exhibits a direct action with minimum rebound as it snaps to its normal position.

It is therefore seen that the basic concept of our invention resides in the use of a stop means to prevent the entry of the auxiliary blade into the arc chute chamber during closing of the switch until contact has been made by the main blade. As a further concept the auxiliary blade is biased in both directions about its pivotal engagement with the main blade to thereby impart rapid movement through the arc chute chamber during both switch opening and closing.

It is therefore a primary object of this invention to provide a load break interrupter switch wherein the auxiliary blade is prevented from entering the arc chute chamber during closing until the main blade has made contact.

A further object of this invention is to provide a load break interrupter switch which includes a stop means in the path of the auxiliary blade to appropriately limit its entry into the arc chute chamber during switch closing.

Another object of this invention is to provide such a load break interrupter switch wherein the stop means offers little resistance to the auxiliary blade during opening of the switch.

An additional object of this invention is to provide such a load break interrupter switch wherein the auxiliary blade is biased in both directions with respect to its pivotal engagement to the main blade, to thereby provide rapid movement during both switch opening and closing.

Still another object of this invention is to provide such a load break interrupter switch which includes a simplified mechanism in which a single spring provides the dual directional biasing.

Still a further object of this invention is to provide such a load break interrupter switch wherein the biasing spring is preloaded to maintain the relative positions of the main auxiliary blades, and provide for direct movement of the auxiliary blade to its normal position with minimum rebound.

These as Well as other objects of this invention will readily become apparent after reading the following d scriptions of the accompanying drawings in which:

FIGURE 1 is a side elevational view of a load break interrupter switch arranged in accordance with the teachings of our invention, showing the contacts in the fully closed position.

FIGURE 2 is a plan view of the load break interrupter switch shown in FIGURE 1.

FIGURES 3 and 4 are side elevation views of the load break interrupter switch shown in the intermediate and fully opened positions respectively.

FIGURE 5 is a side elevation of the load break interrupter switch shown in an intermediate position during closing.

FIGURES 6 and 6a are plan and side elevation views respectively of a typical stop which may be connected to the arc chute chamber to embody the concepts of our invention.

FIGURE 7 is a perspective View showing the preferred auxiliary blade biasing arrangement of our invention.

FIGURES 8 and 8a are side elevation and plan views respectively of the auxiliary blade.

FIGURES 9 and 9a are plan and side elevation views respectively of the auxiliary blade biasin spring.

FIGURES 10 and 10a are plan and side elevation views respectively of a spring stop means which may be used in conjunction with the biasing means of FIGURE 9 to appropriately load the spring during opening and closing operation of the interrupter switch.

Referring now to the figures wherein like numerals define like elements, FIGURES 1 and 2 illustrate a conventional load break interrupter switch ltl modified in accordance with the teachings of our invention. Switch It is comprised of a pair of supporting insulators 11 and I2, such as porcelain insulators and the like, onto which the load interrupter is mounted. The insulators l1 and 12 are mounted to a base or support means 13 in any suitable manner. Back connected insulators 14 and 15 are secured to 13 when required, the insulators 1d and 15 being provided with contact nuts 16 and 1'7 respectively for mounting the circuit to be protected. When the back connected mode of FIGURE 1 is not utilized, then the terminals Z2 and 33 are electrically connected to the circuit to be protected. Alternatively, terminals 22 and 33 may be removed when back connections 14, 15 are employed. Base 13 is provided with apertures 18 and 19 for mount ing to a support means in an appropriate manner.

Insulator 11 has a unitary molded terminal 29 secured thereon by fasteners 21. The integral terminal portion 22 of terminal member it having apertures 23 therethrough, provides the means for connecting the line conductor thereto. Integral hinge tongue 24 of terminal member pivotally connects the load conductor main switch blade 28 which is secured to an aperture in hinge tongue 24 by means of fasteners 27. Electrical contact pressure is supplied at the hinge by stop nuts 26 and washers which cooperate with fasteners 27, thereby providing a uniform contact pressure between blade 23 and tongue 24.

As is more clearly shown in FIGURE 2, switch blade 28 is preferably of a split construction including individual spaced blade sides 29. The individul blade sides 29 are pivotally mounted on the hinge tongue 24 with the sides located on the opposite sides of the hinge tongue respectlvely.

The insulator I2 located at the disconnect end of the load break interrupter switch is also provided with a unitary terminal member 30 which is supported to terminal 12 by fastener 3 Apertures 33 are provided in the terminal portion 32 of unitary terminal member 30 for connection of a line thereto. The unitary terminal 3 is provided with an inter-gap upstanding break tongue 34, which is slotted at its outer end as shown at 35 to receive a bolt 36, which serves to secure the break ends of main switch blade sides 29. The bolt 36 extends through the blade sides 29 at stop nuts 37 and 38 to maintain the break sides together. A spacing sleeve 36' is provided on fastener 36 between break sides 29 for preventing undue movement of the blade sides towards each other. The projections and 46*, which form the slot 35 of tongue 34-, are arranged so that projection 39 is longer than projection 40, for a purpose to be more fully described.

Auxiliary switch blade 41 is pivotally mounted to main switch blade 28 by a fastening means at 43. The fastening means includes a torsion spring and spring stop means 45, which operatively engage end of the auxiliary blade during opening and closing of the switch, to thereby load the auxiliary blade for rapid movement into and out of engagement with its respective contacts.

Auxiliary blade I is operatively positioned to enter arc chute 5% during operation of the switch. Arc chute includes a narrow passageway 51 between opposed walls 53, 54 for the reception of auxiliary blade ill. Passageway 51 is preferably made just slightly larger than the thickness of auxiliary blade 41, allowing only a small clearance between the blade and the insulating wall members 53 and S4. Arc chute 56 further includes a pair of biased auxiliary contacts 52 electrically connected to main stationary contact 39. The inner walls facing narrow passageway 51 are lined with a material having high gas evolving extinguishing properties secured to the internal surfaces of walls 53, 54 in any well known manner. The gases which are evolved within the arc chute during operation of the switch act to extinguish the arc in a manner well known in the art. As an alternative to a gas evolving liner, an arc chute 56 may be formed entirely of gas evolving material, thereby avoiding the necessity of providing a separable liner, and also reducing the number of parts required to form the arc chute.

In accordance with our invention a stop means 60 is fastened to are chute 50 and maintained in the path of blade 41 during closing of load break interrupter 10. Stop 60 prevents auxiliary blade 41 from entering arc chute passageway 51 until main blade 28 has engaged break tongue 34, as will be subsequently more fully described.

Load interrupter it) opens in a conventional manner, as follows:

As shown in FIGURE 1 the load break interrupter switch It is in its normal closed position with the main switch blade 28 in engagement with its main contact tongue 34- and with the auxiliary switch blade ll being received between biased contacts 52 in arc chute 50. When it is desired to interrupt the circuit protected by lead break interrupter switch Ill, switch blade 23 is moved by an appropriate actuating means (not shown) in a direction to move the main blade clockwise about hinge tongue 24, thereby moving the blade 26 from the position shown in FIGURE 1 to that shown in FIGURE 3. This rotation separates main blade 23 from contact tongue 34. Auxiliary blade 41 is held in its closed position by the biasing effect of contacts 52. Thus, auxiliary blade 41 will be angularly separated from main blade 28 about pivot 43. This angular separation between the blades serves to load torsion spring 44, thereby urging auxiliary blade 41 out of engagement with bias contacts 52 and into a substantially parallel position with respect to main blade 28. Disengagement of the auxiliary blade 41 is eifected when main blade 28 has been sufiiciently removed from its associated contact, break tongue 34, to prevent the striking of an arc therebetween upon the opening of the circuit. During the trip position shown in FIGURE 3 wherein main blade 23 is disengaged from its contact tongue 34, a current path is provided between terminals 22 and 32 via auxiliary blade 41 and contact means 52. When main blade 28 has been sufliciently separated from stationary contact tongue 34, auxiliary blade 41 is rapidly disengaged from contact 52 by virtue of loaded spring member 44. The rapid movement of auxiliary movement of auxiliary blade 41 through the arc chute 50 acts to extinguish any arc formed due to the separation of auxiliary blade 41 from contacts 52. It will be noted that stop means 60 is disposed in the path of movement of auxiliary blade 41. However, stop means 61 is preferably biased by torsion spring 73 in the direction shown by arrow 70, and offers little resistance to the movement of auxiliary blade 41 during disengagement of the switch.

The operation thus far described is in many respects conventional, whereby an auxiliary blade contact disposed in an arc chute serves to rapidly disconnect the load interrupter from the circuit. Our invention, as will be subsequently set forth, is more specifically directed to the manner of closing such a switch, whereby the auxiliary blade 41 is kept out of arc chute 5%) until electrical contact has been made between main blade 28 and its contact tongue 34. In the heretofore practiced operation of such load break switches, main break blade 28 is moved in a counter-clockwise direction from its open position shown in FIGURE 4. Projection 39 of contact tongue 34 which preferably includes a ball-shaped tip, makes first contact with main blade 28. Projection 39 is appropriately positioned with respect to auxiliary contacts 52 such that electrical contact is made by the main blade 28, prior to electrical contact being made by the auxiliary blade 41. However, it will be noted that should the main and auxiliary blades remain in their substantially parallel relationship during switch closing, auxiliary blade 41 will be disposed within arc chute passageway 51 prior to engagement of the main blade. It has been found that although the auxiliary blade contact is not made before the main contact, decreased resistance within the arc chute caused by prior arcing permits a break-down from the auxiliary blade 41 to its contacts 52 before the main contacts are made. Once such arcing takes place, the condition of the arcing chamber rapidly deteriorates, causing deleterious deposits which have been found to reduce the number of successful switch operations from 120 to less than 25, under certain conditions of voltage, current and power factor.

To thereby avoid this deleterious effect, our invention keeps auxiliary blade 41 completely out of arc chute passageway 51 until contact has been made between main blade 28 andits contact tongue 34. Once the main contact has been made, the biased interconnection of the main and auxiliary blades at pivot 43 rapidly moves the auxiliary blade through the arc chute into firm engagement with contacts 52.

The operation during closing may best be understood by referring to FIGURE 5, which illustrates the switch in an intermediate position during closing. Stop 60 appropriately connected by bolt 59 to are chute 50 is positioned in the path of auxiliary blade 41 during the closing operation. Hence, it is seen that as main blade 28 is moved counter-clockwise towards engagement with its contact tongue 34, stop 60 prevents associated movement of auxiliary blade 41, thereby angularly separating the blades. Biased pivot 43 is preferably arranged, as will be more fully set forth in conjunction with FIGURE 6, to urge auxiliary blade 41 towards its contact 52. As the angular separation between the blades increases, the torsional loading of spring 44 similarly increases. The lower end 45 of auxiliary blade 41 is appropriately shaped in conjunction with the torsional loading of spring 44, such that auxiliary blade 41 will be released from stop 68 upon engagement of main blade 28 and contact tongue 34. Upon such engagement spring 44 is rapidly unloaded, thereby snapping auxiliary blade 41 rapidly through arc chute passageway 51 and into engagement with auxiliary contacts 52.

Stop 60 is preferably biased by spring 73 to act as an impediment in the path of auxiliary blade 41 during closing operation only. As shown in FIGURE 6, stop 61 is typically shown comprising a rigid rod 71 connected to a flipper-like member 72, spring biased by torsion spring 73 to act only as a stop during closing. That is, during the closing operation lower end 45 of auxiliary blade 41 will engage upper end of stop pin '71, thereby bearing down against the top surface of the are chute to maintain the stop in its obstructing position. During the opening operation of the switch, upper surface 46 of auxiliary blade 41 forcefully strikes lower surface of obstructing member '71, thereby rapidly moving stop 60 out of its path of movement against the biasing effect of spring 73.

Reference is now made to FIGURES 7-10 which illustrate a preferred embodiment of the pivotal engagement between the auxiliary and main blades to provide biasing of the auxiliary blade as it is deflected either upward or downward with respect to its normal position parallel to main blade 28. Torsion spring 44 is disposed about pivot point 43 and opcratively connected to end 42 of the auxiliary blade to provide the aforesaid biasing. Spring stop 75 includes projections 76 and 77 which appropriately interact with spring 44 and blade end 42 to provide the proper amount of spring biasing. Referring first to the operation during opening, auxiliary blade 41 will be deflected at the direction shown by arrow 78 in FIGURE 7. Surface 42' of auxiliary blade 41 will engage end 44, of spring 44, causing it to be forced upward. The other end 44 of spring 44 will be held against rotation by the projection 76 of stop member 75. When the proper angular displacement of the auxiliary blade 41 occurs, corresponding to sufficient separation of main blade 28 from its contact tongue 34, lower auxiliary blade end 42 engages hook portion 77 of stop 75, thereby preventing further angular separation of the auxiliary and main blades. Auxiliary blade 41 is then pulled out of engagement with contacts 52, with spring 44 rapidly unloading to provide quick disengagement.

During closing of the switch, auxiliary blade 41 is deflected in the opposite direction, with lower end 42" engaging spring end 44". Projection 76 of spring stop member 75 engages end 44' of spring 44 thereby causing spring 44 to be loaded. As the angular separation increases corresponding to the engagement of main blade 28 and contact 34, the torsional loading of spring member 44 correspondingly increases. Lower end 45 slides over member 71 during closing until auxiliary blade 41 finally slips from stop 60. Torsional spring 44 is rapidly unloaded, thereby providing a quicksnap action of auxiliary blade 41 through arc chute passageway 51 and into firm engagement with bias contacts 52.

Spring 44 is preferably preloaded corresponding to the normal position of the auxiliary and main blades in their substantially parallel relationship to thereby minimize rebounding of the blade when it is snapped towards its normal position from either deflected position.

It is therefore seen that we have provided an improved loadbreak interrupter switch, wherein the auxiliary blade is prevented from entering the arc chute during the closing operation until engagement has been made by the main contact blade. Such a structure prevents arcing between the auxiliary blade and its contact during the closing operation, and has been found to provide an appreciable increase in the number of operations of the switch.

Although the present invention has been set forth in conjunction with a preferred embodiment, it is naturally understood that many variations and modifications will now become apparent to those skilled in the art, as for example the biased pivotal engagement of the main and auxiliary blades may be provided by numerous other arrangements. Likewise, the stop means disposed in the path of the auxiliary blade during closing may take various other suitable forms. Accordingly, we prefer not to be limited to the specific disclosure herein but only by the appended claims.

Tie embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows.

We claim:

1. In combination first and second terminals; main blade means pivotally connected to said first terminal for movement in a first diretcion to engage said second terminal, and a second direction to disengage said second terminal; auxiliary blade means pivotally mounted to said main blade means; an arc chute having sidewalls and a passageway therebetween for receiving said auxiliary blade means mounted adjacent said second terminal; said passageway containing auxiliary contact means operatively positioned to engage said auxiliary blade means; stop means restraining the entry of said auxiliary blade into said passageway during movement of said main blade in said first direction; means releasing said auxiliary blade from said stop means upon engagement of said main blade and said second terminal; said stop means comprising a first member positioned atop said sidewalls of said arc chute, and positioned to obtstruct said passageway in the path of said auxiliary blade, first biasing means operatively connected to said main and auxiliary blade to urge said auxiliary blade towards said auxiliary contact during movement in said first direction; said stop means loading said first biasing means; said first biasing means operatively connected to said auxiliary blade to impart rapid movement of said auxiliary blade into engagement with said auxiliary contact upon release from said stop means.

2. In combination first and second terminals; main blade means pivotally connected to said first terminal for movement in a first direction to engage said second terminal, and a second direction to disengage said second terminal; auxiliary blade means pivotally mounted to said main blade means; an arc chute having sidewalls and a passageway therebetween for receiving said auxiliary blade means mounted adjacent said second terminal; said passageway containing auxiliary contact means operatively positioned to engage said auxiliary blade means; stop means restraining the entry of said auxiliary blade into said passageway during movement of said main blade in said first direction; means releasing said auxiliary blade from said stop means upon engagement of said main blade and said second terminal; said stop means comprising a first member positioned atop said sidewalls of said are chute, and positioned to obstruct said passageway in the path of said auxiliary blade, and a second member biasing said first member towards said obstructing position; said second member releasably removing said first member from the path of said auxiliary blade during movement in said second direction first biasing means operatively connected to said main and auxiliary blade to urge said auxiliary blade towards said auxiliary contact during movement in said first direction; said stop means loading said first biasing means; said first biasing means operatively connected to said auxiliary blade to impart rapid movement of said auxiliary blade into engagement with said auxiliary contact upon release from said stop means.

3. In combination first and second terminals; main blade means pivotally connected to said first terminal for movement in a first direction to engage said second terminal, and a second direction to disengage said second trminal; auxiliary blade means pivotally mounted to said main blade means; said main and said auxiliary blade means being adapted to be connectable to a source of electric pov er; an arc chute having sidewalls and a passageway thercbctween for receiving said auxiliary blade means mounted adjacent said second terminal; said passageway containing auxiliary contact means being adapted to be connectable to said source of electric power and operatively positioned to engage said auxiliary blade means; first stop means restraining the entry of said auxiliary blade into said passageway during movement of said main blade in said first direction; said first stop means being electrically independent; said first stop means comprising an abutment member secured to a flipper; stop biasmcans urging said flipper in a direction to present said abutment member in the path of said auxiliary blade; said stop biasing means operatively connected to said flipper to releasably remove said abutment member from the path of said auxiliary blade durin its movement in said first direction, said abutment member of said first stop means positioned atop said sidewalls of said are chute; means releasing said auxiliary blade from said first stop means upon engagement of said main blade and said second terminal; first biasing means operatively connected to said main and auxiliary blade to urge said auxiliary blade towards said auxiliary contact during movement in said first direction; said first stop means loading said first biasing mean said first biasing means operatively connected to said auxiliary blade to impart rapid movement of said auxiliary blade into engagement with said auxiliary contact upon reelase from said first stop means; means maintaining engagement of said auxiliary blade and contact means during movement of said main blade in said second direction, and until a predetermined angular separation is established between said auxiliary and main blades; second biasing means operatively connected to said main and auxiliary blades to urge said auxiliary blade out of engagement with said auxiliary contact means; said second biasing means operatively connect d to said auxiliary blade to impart rapid disengagement of said contact means; said first and second biasing means comprising a single spring disposed about the pivotal engagement of said main and auxiliary blades; an end of said spring operatively engaging said auxiliary blade during relative angular movement of said blades; second spring stop means maintaining the position of the opposite spring end, whereby said spring is loaded during said relative angular blade movement.

4. A load-break interrupter switch including: an aux iliary switch blade being adapted to be connectable to a source of electric power; an arc chute; said are chute comprising first and second arc chute sidewalls defining a passageway for the entry of said auxiliary blade; said passageway containing auxiliary contact means being adapted to be connectable to a source of electric power and operatively positioned to engage said auxiliary blade means; the blade entering surface of said are chute passageway having positioned atop it a stop means positioned in the path of said auxiliary blade; said stop means 0bstructing the entry of said auxiliary blade into said passageway; said stop means comprising an abutment member secured to a flipper; stop biasing means urging Said flipper in a direction to present said abutment member in the path of said auxiliary blade; said stop biasing means operatively connected to said flipper to releasably remove said abutment member from the path of said auxiliary blade during opening of said switch.

5. In combination first and second terminals; main blade means pivotally connected to said first terminal for 9 movement in a first direction to engage said second terminal, and a second direction to disengage said second terminal; auxiliary blade means pivotally mounted to said main blade means; said main and said auxiliary blade means being adapted to be connectable to a source of electric power; an arc chute having side Walls and a passageway therebetween for receiving said auxiliary blade means mounted adjacent said second terminal; said passageway containing auxiliary contact means being adapted to be connectable to said source of electric power and operatively positioned to engage said auxiliary blade means; stop means restraining the entry of said auxiliary blade into said passageway during movement of said main blade in said first direction; said stop means being electrically independent; means releasing said auxiliary blade from said stop means upon engagement of said main blade and said second terminal; said stop means comprising a first member positioned atop said sidewalls of said are chute, and positioned to obstruct said passageway in the path of said auxiliary blade, and a second member biasing said first member towards said obstructing position; said second member releasably removing said first member from the path of said auxiliary blade during movement in said second direction; first biasing means operatively connected to said main and auxiliary blade to urge said auxiliary blade towards said auxiliary contact during movement in said first direction; said stop means loading said first biasing means; said first biasing means operatively connected to said auxiliary blade to impart rapid movement of said auxiliary blade into engagement with said auxiliary contact upon release from said stop means.

References Cited by the Examiner UNITED STATES PATENTS 2,571,864 10/51 Graybill 200146 2,840,671 6/60 Gieifers 20062 BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCI-IAEFER, Examiner. 

1. IN COMBINATION FIRST AND SECOND TERMINALS; MAIN BLADE MEANS PIVOTALLY CONNECTED TO SAID FIRST TERMINAL FOR MOVEMENT IN A FIRST DIRECTION TO ENGAGE SAID SECOND TERMINAL, AND A SECOND DIRECTION TO DISENGAGE SAID SECOND TERMINAL; AUXILIARY BLADE MEANS PIVOTALLY MOUNTED TO SAID MAIN BLADE MEANS; AN ARC CHUTE HAVING SIDEWALLS AND A PASSAGEWAY THEREBETWEEN FOR RECEIVING SAID AUXILIARY BLADE MEANS MOUNTED ADJACENT SAID SECOND TERMINAL; SAID PASSAGEWAY CONTAINING AUXILIARY CONTACT MEANS OPERATIVELY POSITIONED TO ENGAGE SAID AUXILIARY BLADE MEANS; STOP MEANS RESTRAINING THE ENTRY OF SAID AUXILIARY BLADE INTO SAID PASSAGEWAY DURING MOVEMENT OF SAID MAIN BLADE IN SAID FIRST DIRECTION; MEANS RELEASING SAID AUXILIARY BLADE FROM SAID STOP MEANS UPON ENGAGEMENT OF SAID MAIN BLADE AND SAID SECOND TERMINAL; SAID STOP MEANS COMPRISING A FIRST MEMBER POSITIONED ATOP SAID SIDEWALLS OF SAID ARC CHUTE, AND POSITIONED TO OBSTRUCT SAID PASSAGEWAY IN THE PATH OF SAID AUXILIARY BLADE, FIRST BIASING MEANS OPERATIVELY CONNECTED TO SAID MAIN AND AUXILAIRY BLADE TO URGE SAID AUXILAIRY BLADE TOWARDS SAID AUXILIARY CONTACT DURING MOVEMENT IN SAID FIRST DIRECTION; SAID STOP MEANS LOADING SAID FIRST BIASING MEANS; SAID FIRST BIASING MEANS OPERATIVELY CONNECTED TO SAID AUXILIARY BLADE TO IMPART RAPID MOVEMENT OF SAID AUXILIARY BLADE INTO ENGAGEMENT WITH SAID AUXILIARY CONTACT UPON RELEASE FROM SAID STOP MEANS. 